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arXiv 1409.7199hep-thastro-ph.COgr-qchep-ph
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隐藏的类扁平宇宙:由f(T)引力引起的类Starobinsky暴胀

The Hidden Flat Like Universe: Starobinsky-like inflation induced by f(T) gravity

W. El Hanafy, G. G. L. Nashed

摘要:

本文研究了$f(T)$引力理论支配下的类扁平宇宙(FLU)中的单一流体组分,其中$T$是平行扭转标量。无论空间曲率$k$的值如何,FLU模型都确定了一类特殊的$f(T)$引力理论。值得注意的是,FLU $f(T)$引力并没有简化为遥平行引力理论。在大的哈勃时空中,这个理论与暴胀宇宙的假设是一致的,并且遵守守恒原理。状态方程(EoS)在所有模型$k=0, \pm 1$中的演变相似。我们研究了挠率张量由标量场构成的情况,这使得我们能够从所得到的$f(T)$引力理论导出一个精粹势。该势函数不需要保角变换就能自然地生成类Starobinsky模型,并在Starobinsky模型和二次暴胀模型之间连续插值高阶。慢滚分析显示了双解,因此对于标量倾斜(光谱指数)$n_{s}$的单个值,该理论可以预测$E$模式和$B$模式偏振的双张量-标量比$r$。

英文摘要:

We study a single fluid component in a flat like universe (FLU) governed by $f(T)$ gravity theories, where $T$ is the teleparallel torsion scalar. The FLU model, regardless the value of the spatial curvature $k$, identifies a special class of $f(T)$ gravity theories. Remarkably, the FLU $f(T)$ gravity does not reduce to teleparallel gravity theory. In large Hubble spacetime the theory is consistent with the inflationary universe scenario and respects the conservation principle. The equation of state (EoS) evolves similarly in all models $k=0, \pm 1$. We study the case when the torsion tensor is made of a scalar field, which enables to derive a quintessence potential from the obtained $f(T)$ gravity theory. The potential produces Starobinsky-like model naturally without using a conformal transformation, with higher orders continuously interpolate between Starobinsky and quadratic inflation models. The slow-roll analysis shows double solutions so that for a single value of the scalar tilt (spectral index) $n_{s}$ the theory can predict double tensor-to-scalar ratios $r$ of $E$-mode and $B$-mode polarizations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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